. The ultimate goal of this research is to improve the treatment of tuberculosis in HIV positive and HIV negative patients and to develop new pharmacologic data that will facilitate further tuberculosis research. The specific aims are to determine and compare: a) the plasma pharmacokinetics of orally administered antituberculous agents, specifically isoniazid, rifampin, pyrazinamide, ethambutol and ethionamide in HIV positive and HIV negative men and women and b) the intrapulmonary pharmacokinetics of the above drugs in the same groups by measuring drug concentrations in bronchoalveolar lavage (BAL) fluid and alveolar cells (AC) and by estimating drug concentrations in pulmonary epithelial lining fluid (ELF). The overall strategy will be to administer one of five anti- tuberculous drugs, i.e. isoniazid, rifampin, pyrazinamide, ethambutol and ethionamide, to healthy subjects and AIDS patients for five days and then, four hours after the last dose, assess the intrapulmonary and plasma concentrations of the drugs.